Modeled current distribution inside the normal and malignant human urothelium using finite element analysis

When the tissue is changing from normal to abnormal, the distribution of tissue liquids between intra and extra cellular space will be changed and then the measured conductivity and impedivity will also be changed. Therefore, it will cause a different current distribution inside the human bladder tissue in normal and malignant cases. By knowing the amount of electrical impedance inside the bladder tissue and the morphological parameters of the different layers of this tissue, the current distribution inside the bladder tissue (surface fluid, superficial urothelium, intermediate urothelium, basal urothelium, basement membrane, and connective tissue) was modelled and calculated in different frequencies using the finite element analysis. The model results showed that very little of the current actually flows through the urothelium and much of the injected current flows through the connective tissue beneath the urothelium (in normal cases). However, most of the current flows through the surface fluid in the low frequency range in normal tissue. Furthermore, for the high frequencies, the tight junctions are short-circuited, so the current penetrates deeper, flowing through the connective tissue beneath the urothelium, while, in the malignant cases, at least 50% of the injected current flows beneath transformed urothelium across the frequency range modelled.